W. Susaki, S. Kakuda, T. Inada, T. Igawa, A. Tomioka, "Determination of Band Offset and Subband Levels for a GaIinP/AlGaInP Quantum Well Laser by Photoreflectance Using a 410nm InGaN Laser with Direct Current Modulation", the 29th International Conference on the Physics of Semiconductors, Rio de Janeiro, Brazil, July 27 - August 1 (2008)